Basic instructions to degree your motor
Put the piston at top dead center by eye
Attach the wheel and mount a sharpened heavy wire pointer off something solid, I use a couple of the reed cage bolts allot of times but as long as it's solid you are fine no matter where you mount it
Have the top dead center or 0 inline with the pointer
Install the piston stop
A piston stop can be a small piece of flat stock fastened down with the cylinder head nuts if the the top of the dome comes out the cylinder.
If it does not, then just drill and tap a hole in the center of the bar so you can thread a bolt in it to reach down into the cylinder.
Turn the crank counter clockwise for the Before TDC # , (the kickstart works good for this but put your hand in the cylinder to slow the piston down so it doesn't slam against the stop with the piston dome)
Write down the number you see on the wheel, for example we will say 18 is on the wheel
Now turn the motor clockwise until you are against the piston stop again, this will be your After TDC # ( when turning clockwise be careful that you do not move the degree wheel if you are going to turn it from the nut holding the wheel on)
Write down the number you see on the wheel, for example we will say 14 is on the wheel
So now we need to move the wheel or move the pointer, we will want to split the difference of 18 and 14 which will be 16
So with the piston against the piston stop either roll the wheel 2 degrees or mover the pointer 2 degrees so it at 16 degrees.
So you should now be at 16 degrees After TDC and now turn the motor counter clock wise again back to Before TDC and it should also be at 16 degrees, if not slightly adjust the pointer so it is. But always keep rolling the motor back and forth until your wheel gives you the same amount of degrees Before and After TDC.
Once you have done this you have found the true TDC
Now you can remove or leave the piston stop, I leave it on and sometimes double check that it still ok if I bump the pointer while working.
Now you can check your exhaust port numbers, I don't count the bevel of the port but some people do so porting numbers are different among builders.
If your exhaust port opens at:
90 than you have 180 degrees of exhaust port duration ( amount of crank degrees the port is open)
88- 184
86 - 188
84 - 192
82 - 196
80 - 200
78 - 204
The transfers get a little tricky depending on your degree wheel
I use a motion pro and after the the 90 degree mark the numbers start to count downward back to zero at BDC
So I can explain this so all wheels make sense I will give both ways
The first number given is a degree wheel that is 0 to 360 degrees
The second is a typical MotionPro style with 0 to 90 then 90 to 0
Third number is the total amount of crank egress the transfer port is open ( transfer port duration)
transfers opening at:
118 or 62 = 124 transfer port duration
117 or 63 = 126
116 or 64 = 128
115 or 65 = 130
114 or 66 = 132
113 or 67 = 134
